Problem: Ishaan ate 3 slices of pie. Christopher ate 4 slices. If there were initially 9 slices, what fraction of the pie was eaten?
Solution: $\text{fraction of pie eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ They ate ${7}$ out of $9$ slices. They ate $\dfrac{7}{9}$ of the pie.